The present invention relates to a pressure reducing control unit, in particular for motor vehicle brake systems, the pressure control unit lying in the pressure medium connection between a master cylinder and at least one slave cylinder and comprising at least one differential piston having a pressure medium passage disposed in a housing, which is acted upon by the force of a control spring, and a valve which is operable dependent on the displacement of the differential piston.
Such a pressure control unit is disclosed in the U.S. Pat. No. 3,727,989 issued Apr. 17, 1973. However, the known pressure control unit is characterized by a long constructional length and a heavy weight. Further, the machining and assembly of the pressure control unit are very extensive since the housing bore which is stepped several times has to be made from two sides and since the assembly of the individual part is also effected from two sides. This also implies the need of inserting an additional closure member with seals.
Further, the known pressure control unit has some functional disadvantages due to the specific design of the valve.